Chromatography Forum

Hi everyone,

I have a problem with my Varian Saturn 2000 MS / 3800GC. 4 days ago I cleaned the ion source and baked the system out up to now, but the water level have not eliminated completely and is reached to "maybe". I also conditioned the moisture trap at 350 0C according to the manual.
Air level was ok during all this time.
Although the water level has improved (from "massive" to "high" to "maybe" ) but the water is not ok for MS work. What can I do for solve this problem?
The 100% count = 350
Total ion count =3400
m/z 19/18= 45%


Thanks a lot.
Yousefi

As long as the air level is low you are good, a "maybe" water level after a vent doesn't sound like a problem to me.
Can you please write here system temperatures? Also did you tune again after the bakeout? If not i would try a tune and then check water level again.

Hi Dear Balbo

I turned off my GC-MS and vented it for changing the transfer line ferrule (I was suspect maybe there is a small leak at this point). After 24 hours, the previous state is continuing as before except with lower intensities for air (half of the previous count).
I also regenerated the moisture trap.

When I select "Air/Water check" , the ratio of m/z of 19 to m/z of 18 is about 30% and a massage appears stating that "Problems found". If I'm allowed to do Tune? Isn't it a risk for the MS? Should I do a complete Tune (FC-43, EMT, ... ) or only a FC-43 (cal gas) tune?

Temperature for bakeout:
Trap: 240 , Manifold: 120 Transferline: 170

Total ion current at Air/water checking: 3120
Count at 100% = 370


Also I have four m/z (with nearly equal counts) in Air region instead of two:
m/z= 27.9 9count=120)
m/z= 28.7 9count= 100)
m/z= 30.8 (count= 122)
m/z= 31.8 (count 122)

Nevertheless the Air status is "OK". Why do i have four m/z?


Thanks for your help.

Hi Dear Balbo

I turned off my GC-MS and vented it for changing the transfer line ferrule (I was suspect maybe there is a small leak at this point). After 24 hours, the previous state is continuing as before except with lower intensities for air (half of the previous count).
I also regenerated the moisture trap.

When I select "Air/Water check" , the ratio of m/z of 19 to m/z of 18 is about 30% and a massage appears stating that "Problems found". If I'm allowed to do Tune? Isn't it a risk for the MS? Should I do a complete Tune (FC-43, EMT, ... ) or only a FC-43 (cal gas) tune?

Temperature for bakeout:
Trap: 240 , Manifold: 120 Transferline: 170

Total ion current at Air/water checking: 3120
Count at 100% = 370


Also I have four m/z (with nearly equal counts) in Air region instead of two:
m/z= 27.9 9count=120)
m/z= 28.7 9count= 100)
m/z= 30.8 (count= 122)
m/z= 31.8 (count 122)

Nevertheless the Air status is "OK". Why do i have four m/z?


Thanks for your help.

Hi Dear Balbo

After 38 hours baking out the system, today the level of water changed to "Ok" with total ion count (TIC) of 2120 (at temperature near to baking out condition:trap=220, Transferline=220, Manifold=120 0C) . Then I Tuned the MS (Temperature: trap=150, Transferline=170, Manifold=40 0C) and checked the Air/water level again and found TIC increased to 4110 ! (although the water level is "Ok" !):


Ratio of m/z 19 to m/z 18 is 17%
Total ion current at Air/water checking: 4110
Count at 100% = 583


Also I have four m/z (instead of two) in Air region with increased count in comparison with before Tuning:
m/z= 27.9 (count=412)
m/z= 28.7 9count= 390)
m/z= 30.8 (count= 370)
m/z= 31.8 (count=388)

Air status is "OK".
How these could be explained?


Thanks for your help.